<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>typeof</title>
</head>

<body>
  <script>
    let value = 'null'
    console.log(typeof value);

    let res = (typeof value === "string") ? "'" + value + "'" : String(value)
    console.log(res);

    let o = { a: 1, b: 2 }
    console.log(delete o);
    console.log(delete o.c);
    console.log('c' in o);
    console.log('b' in o);
    console.log(delete o.b);
    console.log('b' in o);


    let q
    let p = 1
    console.log(p && q);
    console.log(p || q);


    let name = 'wct'
    let web = 'baidu.com'
    console.log(tag`${name}`);
    function tag(strings) {
      console.log(strings);
    }
  </script>
</body>

</html>